I was wondering if it'd be possible to download (all/some) the packages for gentoo, burn them onto CD's and use those CDs to install gentoo with... just to save myself the hassle of downloading the packages each time i install.

Install the stage 3 to get a basic system up and running, then having downloaded all of the latest packages and burnt onto CD, copy them into the /usr/portage/distfiles folder. Run an emerge rsync, then when you emerge the packages you want Gentoo will look in the distfiles folder first before trying to download.

There are some pre-built binary packages in gentoo mirror site (in release folder). For instance, X windows, mozilla, and some gnome packages have been built already. You can download these packages, copy to / and tar -jxpf *.tbz2. I save time to compile these packages.
(I tries emerge --usepkg on these binary packages but this does not always work).